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Biomedical subjects

David A McCarron

Publications and source records attributed to David A McCarron.

13 recordsLinked to original sources
PubMed2006

Reducing hypertensive cardiovascular disease risk of African Americans with diet: focus on the facts.

Hypertension is more common and more severe in African Americans than in other population groups in the United States, placing them at increased risk of cardiovascular disease, stroke, and end-stage renal disease. Whereas past efforts to reduce blood pressure (BP) via the diet centered on manipulating isolated nutrients, there are now conclusive data demonstrating that it is not single dietary components but the overall dietary pattern that has the greatest influence on BP. A nutritionally complete diet rich in fruits, vegetables, and low-fat dairy foods has been clearly proven to significantly lower BP in all population groups. This diet, commonly referred to as the Dietary Approaches to Stop Hypertension (DASH) diet, has been tested in randomized, controlled trials emphasizing African American populations and documented the greatest beneficial effects in hypertensive African Americans. Improving diet quality has been shown to be simply implemented without adverse effects such as symptoms of lactose maldigestion. It is also known to beneficially affect other cardiovascular risk factors and is in keeping with dietary recommendations for prevention of some cancers and osteoporosis. This paper reviews the current data relating dietary patterns to BP control, and advocates dietary recommendations that can accomplish their intended objective of enhancing the health of Americans by promoting safe, feasible, and proven-effective means of doing so. In the case of hypertension prevention and treatment, and thus the reduction of cardiovascular disease risk, overall diet quality should be the primary focus of nutritional recommendations.

Black or African American↗
PubMed2005

Low mineral intake is associated with high systolic blood pressure in the Third and Fourth National Health and Nutrition Examination Surveys: could we all be right?

Analysis of the first National Health and Nutrition Examination Survey (NHANES) in 1984 revealed that a dietary pattern low in mineral intake, specifically calcium, potassium, and magnesium, was associated with hypertension in American adults. Using more recent survey data from NHANES III and NHANES IV, we re-examined the validity of this relationship. Blood pressure (BP) and nutrient intake data from 10,033 adult participants in NHANES III and 2311 adults in NHANES IV revealed findings similar to those of the earlier analysis, demonstrating that the association between inadequate mineral consumption and higher BP is valid and has persisted over two decades. Exploring this relationship further, we separated untreated hypertensive persons by hypertension type (systolic, diastolic, or both), and observed that the BP effect of low mineral intake was most pronounced in those with only systolic hypertension. We also observed that sodium intake was significantly lower in the systolic hypertension group and significantly higher in the diastolic hypertension group compared with the other groups. The nutrient pattern in the combined hypertension group was similar to that of the normotensive group. These findings may help to explain the inconsistent responses generally observed in dietary intervention studies, and they highlight the possible importance of tailored nutritional recommendations for hypertension based on hypertension category and individual dietary practices. Although randomized controlled trials are needed to characterize further the relationship between nutrient intake and hypertension type, these findings indicate that dietary management of hypertension may be more effective if the focus is on the overall nutritional profile rather than single-nutrient intake as currently recommended for most patients.

Adult↗
PubMed2005

Symptoms of postpartum depression and breastfeeding.

Despite important health benefits, the presence of depressive symptoms may decrease the prevalence of breastfeeding. The current study assessed the relationship between depressive symptoms and breastfeeding at 6 and 12 weeks postpartum. Participants were recruited from a cohort completing a clinical trial of calcium for prevention of preeclampsia. At 6 weeks postpartum, the Edinburgh Postnatal Depression Scale (EPDS) was completed by mail. At 12 weeks postpartum, the EPDS was completed at an outpatient visit. There was an inverse relationship between depressive symptoms and breastfeeding at 6 weeks postpartum (P<.001) but not at 12 weeks. This relationship persisted even after controlling for prior history of depression, increased life stress, and current psychoactive medication. The results suggest that depressive symptoms early in the postpartum period may lower the prevalence of breastfeeding.

Adult↗
PubMed2004

Estimated healthcare savings associated with adequate dairy food intake.

Medical literature that has coalesced during the past two to three decades has identified adequate intake of nutrients from dairy foods as a common factor in the reduction of the disease burden of several common medical conditions. These include obesity, hypertension, type 2 diabetes, osteoporosis, kidney stones, certain outcomes of pregnancy, and some cancers. Treatment of these disorders, particularly cardiovascular, consumes a significant portion of the United States' healthcare budget. Drawing on accumulated data from prospective longitudinal studies and randomized controlled trials, this article summarizes the evidence of the net benefits of increased dairy food intake on these conditions, their outcomes, and their costs. Estimated improvements in outcomes were combined with available data on annual costs of the respective disorders. From the calculated annual impact, we generated first-year and fifth-year healthcare cost savings that would accrue if adult Americans simply increased their intake of dairy foods to the currently recommended 3 to 4 servings/d. Using conservative estimates of potential benefit, we project first-year savings of approximately 26 billion dollars and 5-year cumulative savings in excess of 200 billion dollars.

Calcium, Dietary↗
PubMed2003

Adequate nutrient intake can reduce cardiovascular disease risk in African Americans.

Cardiovascular disease kills nearly as many Americans each year as the next seven leading causes of death combined. The prevalence of cardiovascular disease and most of its associated risk factors is markedly higher and increasing more rapidly among African Americans than in any other racial or ethnic group. Improving these statistics may be simply a matter of improving diet quality. In recent years, a substantial and growing body of evidence has revealed that dietary patterns complete in all food groups, including nutrient-rich dairy products, are essential for preventing and reducing cardiovascular disease and the conditions that contribute to it. Several cardiovascular risk factors, including hypertension, insulin resistance syndrome, and obesity, have been shown to be positively influenced by dietary patterns that include adequate intake of dairy products. The benefits of nutrient-rich dietary patterns have been specifically tested in randomized, controlled trials emphasizing African American populations. These studies demonstrated proportionally greater benefits for African Americans without evidence of adverse effects such as symptoms of lactose intolerance. As currently promoted for the prevention of certain cancers and osteoporosis, regular consumption of diets that meet recommended nutrient intake levels might also be the most effective approach for reducing cardiovascular disease risk in African Americans.

Black People↗
PubMed2002

Blood pressure and mesenteric resistance arterial function after spaceflight.

Ground studies indicate that spaceflight may diminish vascular contraction. To examine that possibility, vascular function was measured in spontaneously hypertensive rats immediately after an 18-day shuttle flight. Isolated mesenteric resistance arterial responses to cumulative additions of norepinephrine, acetylcholine, and sodium nitroprusside were measured using wire myography within 17 h of landing. After flight, maximal contraction to norepinephrine was attenuated (P < 0.001) as was relaxation to acetylcholine (P < 0.001) and sodium nitroprusside (P < 0.05). At high concentrations, acetylcholine caused vascular contraction in vessels from flight animals but not in vessels from vivarium control animals (P < 0.05). The results are consistent with data from ground studies and indicate that spaceflight causes both endothelial-dependent and endothelial-independent alterations in vascular function. The resulting decrement in vascular function may contribute to orthostatic intolerance after spaceflight.

Acetylcholine↗
PubMed2002

Calcium metabolism and cardiovascular function after spaceflight.

To determine the influence of dietary calcium on spaceflight-induced alterations in calcium metabolism and blood pressure (BP), 9-wk-old spontaneously hypertensive rats, fed either high- (2%) or low-calcium (0.02%) diets, were flown on an 18-day shuttle flight. On landing, flight animals had increased ionized calcium (P < 0.001), elevated parathyroid hormone levels (P < 0.001), reduced calcitonin levels (P < 0.05), unchanged 1,25(OH)(2)D(3) levels, and elevated skull (P < 0.01) and reduced femur bone mineral density. Basal and thrombin-stimulated platelet free calcium (intracellular calcium concentration) were also reduced (P < 0.05). There was a tendency for indirect systolic BP to be reduced in conscious flight animals (P = 0.057). However, mean arterial pressure was elevated (P < 0.001) after anesthesia. Dietary calcium altered all aspects of calcium metabolism (P < 0.001), as well as BP (P < 0.001), but the only interaction with flight was a relatively greater increase in ionized calcium in flight animals fed low- compared with high-calcium diets (P < 0.05). The results indicate that 1) flight-induced disruptions of calcium metabolism are relatively impervious to dietary calcium in the short term, 2) increased ionized calcium did not normalize low-calcium-induced elevations of BP, and 3) parathyroid hormone was paradoxically increased in the high-calcium-fed flight animals after landing.

Animals↗